Due of the differences in the drilling (machining) depth and variable accessibility in implant work, there is a requirement for equipment permitting considerable variation in the lengths of the machining instruments/drills. Sets comprising a large number of machining instruments/drills have therefore been made available hitherto, from which sets instruments/drills of a suitable length have been chosen as the work progresses. A large number of machining instruments complicates the work and is moreover expensive to provide.
The present invention makes use of the knowledge that one or more extension units between the rotary unit and each machining instrument can reduce the number of lengths needed in the machining instruments.